Project Summary The Comparative Pathology Core is an established Core within the University of Pennsylvania School of Veterinary Medicine that has been integrated into the Abramson Cancer Center (ACC) and is presented as a newly established Shared Resource for NCI approval and CCSG funding. As such, the Core will enable the ACC to fulfill the growing needs of members who are using animal models. Amy Durham, MS, VMD, Diplomate of the American College of Veterinary Pathologists (DACVP) and Assistant Professor in the Department of Pathobiology at the School of Veterinary Medicine, developed and directs the Core. Dr. Durham is a board- certified anatomic veterinary pathologist with considerable experience in animal models of cancer, and has been involved in numerous collaborative research projects with members of the ACC and others throughout the Penn campus. Recognition and accurate interpretation of gross and histopathological lesions in animal models is essential for the success of cancer research. Currently, Core pathologists work with ACC members from multiple Research Programs, including Tumor Biology, Cancer Therapeutics, Breast Cancer, Immunobiology, Radiobiology and Imaging, and Pediatric Oncology. Among the services that have been provided are: mouse phenotyping, comprehensive slide evaluation and interpretation, consultation, autopsy training, and photomicroscopy. Additional services utilize the Core's histology laboratory to provide histopathology slide preparation, as well as special histochemical and immunohistochemical staining. Working with the Facility Director, Dr. Durham, is Dr. Elizabeth Buza, who is the Core's Technical Director and lead pathologist. Dr. Buza has expertise in mouse pathology and additional training in mouse models of disease from Novartis and Jackson Labs, and she has worked with Dr. Durham for several years. There are several board-certified anatomic pathologists who support Drs. Durham and Buza, and are available to provide specialty expertise depending on the investigator's particular needs. They include Dr. Julie Engiles (osteopathology), Dr. Elizabeth Mauldin (dermatopathology), and Dr. Melissa Snchez (oral pathology and immunohistochemistry). The Core currently serves 12 ACC members which, represents a doubling in ACC member usage since the announcement of the Core as an ACC Shared Resource in July 2013. Thus, as cancer research using mouse models continues to expand, Core utilization by ACC members is predicted to grow substantially.